Electric-current indicator



(No Model.) F. A. SWAN.

ELECTRIC CURRENT INDICATOR.

No. 342,475. Patented May 25, 1886.

Z 721223323 6 fienlr (y M m7 I I 2 5 716 UNITED STATES PATENT OFFICE.

FREDERIO A. SlVAN, OF EVERETT, MASSACHUSETTS.

ELECTRIC-CURRENT INDICATOR.

SPECIPICATIONtorming part of Letters Patent .NO. 342,475, dated May 25,1886.

Application filed January .2, i886. Serial No. 187,399. (No model.)

To all whom it may concern:

Be it known that I, FREDERIO A. SWAN, of Everett, county ofMiddlesezgand State of Massachusetts, have invented an Improvement inthe dial and pointer removed, the core being broken out to show the plug20; and Figs. 3

Electric Indicators, of which the following do and 4, details to bereferred to. scription, in connection with the accompany- Theinclosing-case A, of wood or other noning drawings, is a specification,like letters on conducting material, and of suitable size to thedrawings representing like parts. contain the working parts of theapparatus, This invention relates to electric indicators is designed tobe attached to the wall of the adapted to be used in electric-lightsystems, to dynamo-room, where it can be plainly seen indicate thestrength of current in the circuit by the attendant in charge. The caseA conin which the indicator is placed, and it is es t-ains within itasolenoid, a, held in place by pecially adapted ,to be used in connectionwith suitable supports, a, only one of which is the usual dial or wallcontroller, com shown, said supports being attached in suitrnonly usedin systems of electric lighting. able manner to said case and secured tosaid 6 In electric-light systems as now used, each solenoid, one at eachend. The wire of the circuit, containing a variable number of lamps,solenoid a has its opposite ends, 2 3, connected is provided with a dialor wall controller, to binding-posts a a to which the line-wires whichgoverns the current in the circuit in are attached, to place theindicator in circuit. which the said dial or wall-controlleris placedThe solenoid a has an iron core, I), preferably The Working condition ofthe different cirhollow at its center, and provided at its oppocuitsextended from a central or current-gem site ends with plugs b and 20.(See Figs. 2 crating station is now judged by observing and 3.) The plugb of the core, at its upper the condition of one lamp of each circuit,such end, is herein shown as provided with uplamp being located withinsaid central stawardly-projectingears, which receive between tion, andalso by means of the length of the them one end ofa link, 0, said linkand ears sparks at the brushes bearing on the commubeing connectedtogether by a pin, 0 inserted tator. through them, said constructionfacilitating The means described by which the .condithe removal of thecore from the solenoid, and tion of each circuit is judged are notsuffiat the same permitting the mechanism for cientl y sensitive toindicate small variations in the strength of the current flowing throughsaid circuits.

The object of this invention is to provide electric-light systems withan indicator which shaft, 0 (see Fig. 4-,) said shaft having bearshallbe sensitive to slight variations in curings in a top and bottom plateof a frame-work, rent-strength; and my invent-ion consists, essaidrack-segment engaging a pinion, c", on a sentially, of a case, a dial, apointer, and mechshaft, 0 to which a pointer, d, is secured, said anism,as will be described, to move said pointer moving overadial, d securedto suppointer, combined with a solenoid having its porting-blocks d,attached to'the frame or 0 core connected to said mechanism, themovecase A, said dial having suitable marks on its ment of said corewithin said solenoid being face, by which to indicate variationsineither transmitted to said pointer through said mechdirection from thenormal, at which it is de anism, to indicate current changes in thecirsired the lamps should be maintained. cuit in which the indicator isplaced. The described mechanism by which the 5 My invention alsoconsists in details of conpointer d is moved may be of any suitable orstruction, to be hereinafter described, and well-known construct-ion,and is herein shown pointed out in the claims 'at the end of this as thewell-knownsteam-gage movement. The specification. solenoid has atube-like extension, b N, closed Figure 1 is a front View of my improvedinat its lower end, which receives the head L moving the pointer to havea wide range of movement. The link 0 at its other end is connected toone end of an adj ustingbar, c adapted to slide on a rack-segment, 0fast on a forming part of a rod, I)", attached to the plug 20 in thelower end of the core I) of the solenoid, the said tube-like extensionand head eon stituting a dash-pot, the tube-like extension containingglycerine or other medium capable of acting as a cushion or check-s11chas commonly used in dash-pots.

The core I) is herein shown as provided at its upper end with lugs I),preferably of brass, which bear against the walls of the hollow cylinderof the solenoid a, as shown in Fig. 2, and act as guides for said core,thus preventing the said core from being attracted laterally, whichlateral attraction would render the indicator insensitive to slightvariations in the strength of the current flowing through the solenoid.The movement of the 'core Z) within the solenoid is steadied by thedash-pot, which also acts as a guide for the lower end of the core 1),to prevent lateral attraction at that end, thus end.

In the operation of my improved indicator" the solenoid a will be sowound as to have the pointer (Z at Zero when a current of normalstrength is passing through the circuit, the current being normal wheneach lamp is burning with proper brillianey and no defects exist in theline or circuit. \Vhcn for any reason such as by the cutting out ofasingle lamp the strength of the current flowing through the circuit isincreased, the solenoid a attracts its core, lifting it up within it,which upward movement causes the rack-segi'nent to move the pointer d tothe right, viewing Fig. 1. If the pointer d remains in a fixed positionat the right for any length of time, the attendant is made aware of afault in the circuit. NVhen the strength of the current is decreased or(ii minished-such as by placing in circuit one ormore lamps, or fromresistances foreign to the circuit the current passing through thesolenoid a is weakened, thereby permitting the core I) to descend bygravity, thus moving the pointer toward the left, the movement of thepointer toward the left being somewhat retarded by the glycerine in thetube b. The

dash-pot referred to prevents the pointer from being moved too rapidlyby sudden fluctuations or changes of current.

It is evident that the cylinder of the solenoid might have ribs of brassextended through it, to serve as fenders against lateral attraction, andthus do away with the fenders if on the core; but I prefer theconstruction shown.

My invention is equally applicable to be used with incandescent lightsystems, the resistance of the solenoid being increased by suitablewinding.

I do not desire to limit myself to the mechanism shown for transmittingthe movement of the core to the pointer, as many forms may be used withequally good results.

I clain1 1. In an electric indicator, a case, a dial, a pointer, andmechanism, substantially as described, to transmit motion to saidpointer, combined with a solenoid, its core connected to said mechanism,and with guides toprevent lateral attraction of said core, as and forthe purpose set forth.

2. In an electric indicator, a case, a dial, a pointer, and mechanism,substantially as de scribed, to transmit motion to said pointer,combined with a solenoid, its core connected to said mechanism andprovided with a guide or guides, to prevent lateral attraction, and witha dashpot to retard, and thereby steady, the movement of the core withinsaid solenoid, as and for the purpose specified.

In an electric indicator, a case, a dial, a pointer, and mechanism,substantially as described, to transmit motion to said pointer, combinedwith a solenoid having its core connectedto said mechanism, the movementof said core within said solenoid being transmitted to said pointer, andwith the dash-pot to steady the movement of said core, as and for thepurpose specified.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FREDERIO A. SNVAN.

Vitnesses;

.T. H. CHURCHILL, G. W. GREGORY.

